Open, Parallel and Randomised Pilot Clinical Trial to Evaluate the Utility of the Therapeutic Monitoring of Plasma Levels of Efavirenz in Hiv-Infected Patients Initiating an Antiretroviral Treatment Regimen With Sustiva

The proportion of patients who need to interrupt treatment with efavirenz due to virological failure [ Time Frame: after 96 weeks of follow-up ] [ Designated as safety issue: Yes ]

Secondary Outcome Measures:

The proportion of patients who need to interrupt treatment with efavirenz due to adverse side effects [ Time Frame: after 96 weeks of follow-up ] [ Designated as safety issue: Yes ]

To determine the incidence of adverse events and the toxicity profile (haemogram, AST/ALT/FA/GGT, creatinine, urea) [ Time Frame: during the 96 weeks of follow-up ] [ Designated as safety issue: Yes ]

To evaluate the proportion of patients with plasma levels of efavirenz between 1.0 and 4.0 mg/L [ Time Frame: during the 96 weeks of follow-up ] [ Designated as safety issue: No ]

To evaluate the relationship between the appearance of secondary events during treatment with efavirenz and the patients' demographic and clinical characteristics, as well the plasma concentration of efavirenz [ Time Frame: during the 96 weeks of follow-up ] [ Designated as safety issue: No ]

To evaluate the variations in CD4 and CD8 lymphocyte count [ Time Frame: during the 96 weeks of follow-up ] [ Designated as safety issue: No ]

Modification of doses of efavirenz guided by its plasma concentration (therapeutic drug monitoring)

Drug: Efavirenz capsules 200 mg and 600 mg

Modification of doses of efavirenz guided by its plasma concentration (therapeutic drug monitoring)

Other Name: Sustiva

Detailed Description:

Currently, efavirenz is dosed systematically, without taking into account the individual characteristics of each individual patient. However, plasma concentration of efavirenz may widely vary between different subjects that receive the same dose of the drug (interindividual variability).

Therapeutic drug monitoring (TDM) signifies individualised pharmacological dosing, based on the plasma levels that each patient presents. This strategy has been broadly used in the field of the treatment of other medical conditions and is acquiring growing interest in the field of antiretroviral treatment. Thus, the use of TDM for the treatment of naïve patients with nelfinavir or with indinavir has translated into an increase in the proportion of individuals with suppressed viral load and also into a reduction in HAART-induced adverse events . However, data on the utility of the therapeutic monitoring of the levels of efavirenz in HIV-infected patients are very scant.

On the basis of the above, it might be thought that the modification of the doses of efavirenz, guided by its plasma concentration, in patients receiving this drug and whose plasma levels of efavirenz are outside the therapeutic range, might improve the tolerability of the treatment without compromising virological efficacy.

Eligibility

Ages Eligible for Study:

18 Years to 65 Years

Genders Eligible for Study:

Both

Accepts Healthy Volunteers:

No

Criteria

Inclusion Criteria:

HIV-1 patients.

According to the criteria of the treating physician, the need to initiate a regimen of antiretroviral treatment that includes efavirenz (both antiretroviral-naive patients and others on treatment with protease inhibitors switching to efavirenz for salvage reasons or for simplification of the anti-retroviral therapy are included).

Absence of opportunistic infections and/or tumours in the three months prior to inclusion.

Exclusion Criteria:

History of allergic hypersensitivity to the investigational drug.

History of previous failure with antiretroviral treatment with non-nucleoside reverse transcriptase inhibitors or previously documented resistance to efavirenz

History of psychiatric comorbidity which, in the investigator's opinion, renders the use of efavirenz inadvisable.

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Please refer to this study by its ClinicalTrials.gov identifier: NCT00299091